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Startup Hook

The purpose of a startup hook is to save your process list and bring it back at machine restarts, even unexpected ones.

Each OS has a specific tool to handle startup hooks: PM2 provides an easy way to generate and configure them.

Installation

To detect available init systems on your machine and generate a configuration, use:

pm2 startup
$ [PM2] You have to run this command as root. Execute the following command:
$ sudo su -c "env PATH=$PATH:/home/unitech/.nvm/versions/node/v4.3/bin pm2 startup <distribution> -u <user> --hp <home-path>

Copy and paste in the CLI the ouput of this command to set up your startup hook.

With NVM, the pm2 path change when updating nodejs. You need to run the startup command after every update.

You can customize the service name via the --service-name <name> option (#3213)

Save your process list

The startup hook auto load the process list that you have previously saved.

Save your process list with:

pm2 save

Warning : if you delete all processes then reboot your system (or use pm2 update) it will ressurect all your processes (previously stored in dump file). It’s to prevent “empty dump file” bug.

If you want to create an empty dump file you should use :

pm2 cleardump

Disabling startup system

pm2 unstartup

User permissions

If you want the startup hook to be executed under another user, use the -u <username> option and the --hp <user_home>:

pm2 startup ubuntu -u www --hp /home/ubuntu

Update startup hook

To update the startup hook run the following commands:

pm2 unstartup
pm2 startup

Compatibility

Init systems supported are:

  • systemd: Ubuntu >= 16, CentOS >= 7, Arch, Debian >= 7
  • upstart: Ubuntu <= 14
  • launchd: Darwin, MacOSx
  • openrc: Gentoo Linux, Arch Linux
  • rcd: FreeBSD
  • systemv: Centos 6, Amazon Linux

You can specify the platform you use if you want to:

pm2 [startup | unstartup] [platform]

Platform can be either one of the cited below:

ubuntu, ubuntu14, ubuntu12, centos, centos6, arch, oracle, amazon, macos, darwin, freebsd, systemd, systemv, upstart, launchd, rcd, openrc

Under the hood

  • ubuntu use updaterc.d and the script lib/scripts/pm2-init.sh
  • centos/redhat use chkconfig and the script lib/scripts/pm2-init-centos.sh
  • gentoo use rc-update and the script lib/scripts/pm2
  • systemd use systemctl and the script lib/scripts/pm2.service
  • darwin use launchd to load a specific plist to resurrect processes after reboot.

Windows consideration

There are some external libraries to generate a Windows compatible startup script, please checkout pm2-windows-service or pm2-windows-startup.

Next Steps

Load-Balancing (cluster mode)